It is known to manufacture wire, e.g. of 5 to 12 mm. in diameter, on a so-called wire manufacturing block which may incorporate 6, 8 or 10 stands positioned sequentially. The stands are usually arranged horizontally with the opposed rolls in each stand displaced 90.degree. in engagement with the wire, so as to maintain the surfaces of the wire and the diameter even. Each stand is equipped with a drive gear, and all gears are connected to one common main gear shaft. The latter is driven, via an intermediate gear, by one motor only.
The gears are designed so that the number of revolutions of the wire engaging rolls for each stand is graduated in accordance with the required degree of elongation desired between the individual stands. Thus, the relationship between individual stands of the scale of the number of revolutions, as well as the elongation degree sequence for the wire block, are rigidly determined and can be altered only by reconstruction of the gear transmission stages. Such reconstruction, however, can be done only during shutdown of the line, and only with great expenditure. Moreover, if the final diameter of the wire rod is to be comparatively large, the rigidly determined elongation degree sequence requires that a large tap or initial diameter be chosen. This, however, requires very high rolling pressures, and even greater rolling momentum. Provisions have been made to obtain the desired large final diameter by bypassing several stands. This makes it possible to tap with a smaller diameter, while maintaining the predetermined elongation degree sequence. However, this solution has the disadvantage of inferior dimensional integrity of the final diameter on account of the residual errors, as these are directly affected by the number of stands in operation engaging the wire.
Another suggestion is to utilize continually controllable gears, such as hydraulic or summation transmissions, to obtain differential elongation degrees. Hydraulic transmissions or other similarly functioning transmissions have the decided disadvantage, however, of allowing slippage in the number of revolutions of the rolls engaging the wire, which cannot be tolerated in continuous rolling mills. Furthermore, the known transmissions have the decided disadvantage that adjustment of velocity stages is very complicated, and therefore causes errors, and these adjustments must be carried out during shutdown of the line.